Thrombolysis and Mechanical Thrombectomy for Acute Ischemic Stroke in Pregnancy: A Case Report.

Objective: Intravenous (IV) recombinant tissue plasminogen activator (rt-PA) and mechanical thrombectomy (MT) are effective treatments for acute ischemic stroke (AIS). However, the treatment for AIS in pregnancy is not established because no clinical trials have included pregnant patients. We present a case of middle cerebral artery (MCA) M2 segment occlusion in pregnancy treated with IV thrombolysis and endovascular therapy. Case Presentation: A 36-year-old woman being 6 weeks pregnant presented with right-sided hemiparesis and aphasia. MRI showed a high-intensity area on diffusion-weighted imaging of the left parietal lobe, and MRA showed left MCA M2 segment occlusion. She underwent IV rt-PA and MT and achieved thrombolysis in cerebral infarction 2b revascularization without complications. The protein S concentration was lower than that in the physiological changes during pregnancy. She was diagnosed with embolic stroke related to coagulopathy in pregnancy, and she underwent anticoagulation. At the 3-month follow-up, the modified Rankin Scale was 0. She miscarried at 4 months, and the fetal death was presumed to be obstetric cause. Conclusion: IV rt-PA and MT may be effective and safe treatments for pregnant patients. Estimated fetal radiation exposure during MT is low and is presumed not to affect fetal development. We should mitigate the radiation dose and reduce the dose of iodinated contrast agents, particularly in pregnant patients.

Neural Processing Mechanism of Mental Calculation Based on Cerebral Oscillatory Changes: A Comparison Between Abacus Experts and Novices.

Background: Abacus experts could mentally calculate fast some mathematical operations using multi-digit numbers. The temporal dynamics of abacus mental calculation are still unknown although some behavioral and neuroimaging studies have suggested a visuospatial and visuomotor neural process during abacus mental calculation. Therefore, this contribution aims to clarify the significant similarities and the differences between experts and novices by investigating calculation-induced neuromagnetic responses based on cerebral oscillatory changes. Methods: Twelve to 13 healthy abacus experts and 17 non-experts participated in two experimental paradigms using non-invasive neuromagnetic measurements. In experiments 1 and 2, the spatial distribution of oscillatory changes presented mental calculations and temporal frequency profiles during addition while examining multiplication tasks. The MEG data were analyzed using synthetic aperture magnetometry (SAM) with an adaptive beamformer to calculate the group average of the spatial distribution of oscillatory changes and their temporal frequency profiles in source-level analyses. Results: Using a group average of the spatial distribution of oscillatory changes, we observed some common brain activities in both right-handed abacus experts and non-experts. In non-experts, we detected the right dorsolateral prefrontal cortex (DLPFC) and bilateral Intraparietal sulcus (IPS); whereas in experts, detected the bilateral parieto-occipital sulcus (POS), right inferior frontal gyrus (IFG), and left sensorimotor areas mainly. Based on the findings generated, we could propose calculation processing models for both abacus experts and non- experts conveniently. Conclusion: The proposed model of calculation processing in abacus experts and novices revealed that the novices could calculate logically depending on numerical processing in the left IPS. In contrast, abacus experts are utilizing spatial processing using a memorized imaginary abacus, which distributed over the bilateral hemispheres in the IFG and sensorimotor areas.

Clipping of Recurrent Cerebral Aneurysms After Coil Embolization.

BACKGROUND AND AIMS: To assess the technical points of surgical clipping for recurrent aneurysms after coiling, we examine a consecutive series of 14 patients who underwent re-treatment. MATERIALS AND METHODS: From 2009 to 2016, 27 recurrent aneurysms after coiling were re-treated with endovascular treatment or surgical clipping. Of these, 14 were re-treated surgically. In cases where the remnant neck was sufficiently large, neck clipping was chosen. Where the remnant neck was too small and the border between the thrombosed and non-thrombosed portion was distinct, partial clipping was chosen. Surgical clipping was attempted without removing the coils when technically feasible. RESULTS: Among the 14 cases, neck clipping was performed in 11, partial clipping in 2, and trapping with bypass in 1 case. Clipping without removal of coils was accomplished in all cases. No neurological deterioration occurred after surgical clipping in any case. CONCLUSION: Clipping of recurrent aneurysms after coiling can compensate for the failure of initial endovascular therapy. For clipping without removal of coils, precise evaluation of the remnant neck is required. Bypass surgery is key to treatment in the case of aneurysm trapping.

A Fully Implantable Wireless ECoG 128-Channel Recording Device for Human Brain-Machine Interfaces: W-HERBS.

Brain-machine interfaces (BMIs) are promising devices that can be used as neuroprostheses by severely disabled individuals. Brain surface electroencephalograms (electrocorticograms, ECoGs) can provide input signals that can then be decoded to enable communication with others and to control intelligent prostheses and home electronics. However, conventional systems use wired ECoG recordings. Therefore, the development of wireless systems for clinical ECoG BMIs is a major goal in the field. We developed a fully implantable ECoG signal recording device for human ECoG BMI, i.e., a wireless human ECoG-based real-time BMI system (W-HERBS). In this system, three-dimensional (3D) high-density subdural multiple electrodes are fitted to the brain surface and ECoG measurement units record 128-channel (ch) ECoG signals at a sampling rate of 1 kHz. The units transfer data to the data and power management unit implanted subcutaneously in the abdomen through a subcutaneous stretchable spiral cable. The data and power management unit then communicates with a workstation outside the body and wirelessly receives 400 mW of power from an external wireless transmitter. The workstation records and analyzes the received data in the frequency domain and controls external devices based on analyses. We investigated the performance of the proposed system. We were able to use W-HERBS to detect sine waves with a 4.8-µV amplitude and a 60-200-Hz bandwidth from the ECoG BMIs. W-HERBS is the first fully implantable ECoG-based BMI system with more than 100 ch. It is capable of recording 128-ch subdural ECoG signals with sufficient input-referred noise (3 µVrms) and with an acceptable time delay (250 ms). The system contributes to the clinical application of high-performance BMIs and to experimental brain research.

Noninvasive spatiotemporal imaging of neural transmission in the subcortical visual pathway.

Spatiotemporal signal transmission in the human subcortical visual pathway has not been directly demonstrated to date. To delineate this signal transmission noninvasively, we investigated the early latency components between 45 ms (P45m) and 75 ms (N75m) of visually-evoked neuromagnetic fields (VEFs). Four healthy volunteers participated in this study. Hemi-visual field light flash stimuli were delivered a total of 1200 times. Neuromagnetic responses were measured with a 160-channel whole-head gradiometer. In three participants, averaged waveforms indicated a subtle but distinct component that peaked with a very early latency at 44.7 ± 2.1 ms with an initial rise latency of 36.8 ± 3.1 ms, followed by a typical prominent cortical component at 75 ms. The moving equivalent current dipoles continuously estimated from P45m to N75m were first localized in the vicinity of the contralateral lateral geniculate body, then rapidly propagated along the optic radiation and finally terminated in the contralateral calcarine fissure. This result indicates that the source of P45m is the lateral geniculate body and that the early latency components P45m-N75m of the VEFs reflect neural transmission in the optic radiation. This is the first report to noninvasively demonstrate the neurophysiological transmission of visual information through the optic radiation.

Frequency-dependent oscillatory neural profiles during imitation.

Imitation is a complex process that includes higher-order cognitive and motor function. This process requires an observation-execution matching system that transforms an observed action into an identical movement. Although the low-gamma band is thought to reflect higher cognitive processes, no studies have focused on it. Here, we used magnetoencephalography (MEG) to examine the neural oscillatory changes including the low-gamma band during imitation. Twelve healthy, right-handed participants performed a finger task consisting of four conditions (imitation, execution, observation, and rest). During the imitation and execution conditions, significant event-related desynchronizations (ERDs) were observed at the left frontal, central, and parietal MEG sensors in the alpha, beta, and low-gamma bands. Functional connectivity analysis at the sensor level revealed an imitation-related connectivity between a group of frontal sensors and a group of parietal sensors in the low-gamma band. Furthermore, source reconstruction with synthetic aperture magnetometry showed significant ERDs in the low-gamma band in the left sensorimotor area and the middle frontal gyrus (MFG) during the imitation condition when compared with the other three conditions. Our results suggest that the oscillatory neural activities of the low-gamma band at the sensorimotor area and MFG play an important role in the observation-execution matching system related to imitation.

Direct Surgery of Previously Coiled Large Internal Carotid Ophthalmic Aneurysm for the Purpose of Optic Nerve Decompression.

Background Progressive visual loss after coil embolization of a large internal carotid ophthalmic aneurysm has been widely reported. It is generally accepted that the primary strategy for this complication should be conservative, including steroid therapy; however, it is not well known as to what approach to take when the conservative therapy is not effective. Case Presentation We report a case of a 55-year-old female presenting with progressive visual loss after the coiling of a ruptured large internal carotid ophthalmic aneurysm. As the conservative therapy had not been effective, we performed neck clipping of the aneurysm with optic canal unroofing, anterior clinoidectomy, and partial removal of the embolized coils for the purpose of optic nerve decompression. After the surgery, the visual symptom was improved markedly. Conclusions It is suggested that direct surgery for the purpose of optic nerve decompression may be one of the options when conservative therapy is not effective for progressive visual disturbance after coil embolization.

Utility of the Lone Star Retractor System in Microsurgical Carotid Endarterectomy.

BACKGROUND: The retractor system is an important device in carotid endarterectomy (CEA). We applied the Lone Star (LS) Retractor System, which is a self-retaining retractor originally designed for improved visualization in many other surgical fields, in microsurgical CEA. METHODS: The LS disposal retractor (14.1 cm × 14.1 cm) and LS elastic stays (5-mm sharp hook) were used as a retractor system in 38 consecutive CEAs. RESULTS: Using the LS retractor system, a shallow operative field could be obtained by lifting up the connective tissue surrounding the deep structures hooked by the LS elastic stays. The LS elastic stays were quick and easy to handle in the microsurgical operative field. There were no complications using the LS retractor system. CONCLUSIONS: The application of the LS retractor system in microsurgical CEA is feasible. An additional merit is that it is single use.

Temporospatial identification of language-related cortical function by a combination of transcranial magnetic stimulation and magnetoencephalography.

INTRODUCTION: Identification of language-related cortical functions can be carried out noninvasively by transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG), which allow for lesion-based interrogation and global temporospatial investigation of cortices, respectively. Combining these two modalities can improve the accuracy of the identification, but the relationships between them remain unclear. We compared TMS and MEG responses during the same language task to elucidate their temporospatial relationships and used the results to develop a novel method to identify language-related cortical functions. METHODS: Twelve healthy right-handed volunteers performed a picture-naming task during TMS and MEG. TMS was applied on the right or left inferior frontal gyrus (IFG) at five time points, and the reaction times (RTs) for naming the pictures were measured. The temporospatial oscillatory changes measured by MEG during the same task were then compared with the TMS results. RESULTS: Transcranial magnetic stimulation of the left IFG significantly lengthened RTs at 300 and 375 msec after picture presentation, whereas TMS of the right IFG did not change RTs significantly. Interestingly, the stimulus time point at which RTs increased significantly for each individual was correlated with when the low gamma event-related desynchronizations (ERDs) peaked in the left IFG. Moreover, combining the results of TMS and MEG improved the detection rate for identifying the laterality of language function. CONCLUSIONS: These results suggest that the low gamma ERDs measured by MEG strongly relate to the language function of picture naming in the left IFG. Finally, we propose a novel method to identify language-related cortical functions by combining TMS and MEG.

Facilitated lexical ambiguity processing by transcranial direct current stimulation over the left inferior frontal cortex.

Previous studies suggest that the left inferior frontal cortex is involved in the resolution of lexical ambiguities for language comprehension. In this study, we hypothesized that processing of lexical ambiguities is improved when the excitability of the left inferior frontal cortex is enhanced. To test the hypothesis, we conducted an experiment with transcranial direct current stimulation (tDCS). We investigated the effect of anodal tDCS over the left inferior frontal cortex on behavioral indexes for semantic judgment on lexically ambiguous and unambiguous words within a context. Supporting the hypothesis, the RT was shorter in the anodal tDCS session than in the sham session for ambiguous words. The results suggest that controlled semantic retrieval and contextual selection were facilitated by anodal tDCS over the left inferior frontal cortex.

Patient-specific cortical electrodes for sulcal and gyral implantation.

PURPOSE: Noninvasive localization of certain brain functions may be mapped on a millimetre level. However, the interelectrode spacing of common clinical brain surface electrodes still remains around 10 mm. Here, we present details on development of electrodes for attaining higher quality electrocorticographic signals for use in functional brain mapping and brain-machine interface (BMI) technologies. METHODS: We used platinum-plate-electrodes of 1-mm diameter to produce sheet electrodes after the creation of individualized molds using a 3-D printer and a press system that sandwiched the electrodes between personalized silicone sheets. RESULTS: We created arrays to fit the surface curvature of the brain and inside the central sulcus, with interelectrode distances of 2.5 mm (a density of 16 times previous standard types). Rat experiments undertaken indicated no long term toxicity. We were also able to custom design, rapidly manufacture, safely implant, and confirm the efficacy of personalized electrodes, including the capability to attain meaningful high-gamma-band information in an amyotrophic lateral sclerosis patient. CONCLUSION: We developed cortical sheet electrodes with a high-spatial resolution, tailor-made to match an individual's brain. SIGNIFICANCE: This sheet electrode may contribute to the higher performance of BMI's.

Alpha band functional connectivity correlates with the performance of brain-machine interfaces to decode real and imagined movements.

Brain signals recorded from the primary motor cortex (M1) are known to serve a significant role in coding the information brain-machine interfaces (BMIs) need to perform real and imagined movements, and also to form several functional networks with motor association areas. However, whether functional networks between M1 and other brain regions, such as these motor association areas, are related to the performance of BMIs is unclear. To examine the relationship between functional connectivity and performance of BMIs, we analyzed the correlation coefficient between performance of neural decoding and functional connectivity over the whole brain using magnetoencephalography. Ten healthy participants were instructed to execute or imagine three simple right upper limb movements. To decode the movement type, we extracted 40 virtual channels in the left M1 via the beam forming approach, and used them as a decoding feature. In addition, seed-based functional connectivities of activities in the alpha band during real and imagined movements were calculated using imaginary coherence. Seed voxels were set as the same virtual channels in M1. After calculating the imaginary coherence in individuals, the correlation coefficient between decoding accuracy and strength of imaginary coherence was calculated over the whole brain. The significant correlations were distributed mainly to motor association areas for both real and imagined movements. These regions largely overlapped with brain regions that had significant connectivity to M1. Our results suggest that use of the strength of functional connectivity between M1 and motor association areas has the potential to improve the performance of BMIs to perform real and imagined movements.

Cerebellar-related long latency motor response in upper limb musculature by transcranial magnetic stimulation of the cerebellum.

In this study, we aimed to identify the cerebellum-related electromyographic (EMG) response that appeared in the upper limbs musculature. Thirty times averaged transcranial magnetic stimulation (TMS) with a double-cone coil placed over the cerebellar hemisphere elicited long latency EMG responses at the bilateral extensor carpi radialis (ECR) muscles. The peak latency of this EMG response was 70.7±12.7 ms in the ipsilateral ECR and 62.9±10.2 ms in the contralateral ECR of the TMS side. These latencies were much longer than the latency of the muscle evoked potential when we stimulated pyramidal tracts at the foramen magnum level. Cerebellar hemisphere loading by the finger target pursuit test made this EMG response faster during TMS on the ipsilateral side of the cerebellum and slower during TMS on the contralateral side of the cerebellum. Furthermore, the deeper the level of drowsiness, the slower the peak latency of this EMG response became. These results suggest that this EMG potential is a specific response of the cerebellum and brainstem reticular formation, and may be conducted from the cerebellar structure to the ECR muscle through the polysynaptic transmission of the reticulospinal tract.

Possible roles of the dominant uncinate fasciculus in naming objects: a case report of intraoperative electrical stimulation on a patient with a brain tumour.

How the dominant uncinate fasciculus (UF) contributes to naming performance is uncertain. In this case report, a patient with an astrocytoma near the dominant UF was given a picture-naming task during intraoperative electrical stimulation in order to resect as much tumourous tissues as possible without impairing the dominant UF function. Here we report that the stimulations with the picture-naming task also provided some insights into how the dominant UF contributes to naming performance. The stimulation induced naming difficulty, verbal paraphasia, and recurrent and continuous perseveration. Moreover, just after producing the incorrect responses, the patient displayed continuous perseveration even though the stimulation had ended. The left UF connects to the inferior frontal lobe, which is necessary for word production, so that the naming difficulty appears to be the result of disrupted word production caused by electrical stimulation of the dominant UF. The verbal paraphasia appears to be due to the failure to select the correct word from semantic memory and the failure to suppress the incorrect word. The left UF is associated with working memory, which plays an important role in recurrent perseveration. The continuous perseveration appears to be due to disturbances in word production and a failure to inhibit an appropriate response. These findings in this case suggest that the dominant UF has multiple roles in the naming of objects.

[Present status and future development of neurophysiological examination in laboratory medicine].

In 2011, nine brain and six nerve and muscle physiological examinations were covered by the national health insurance in Japan. The greatest recent change was the digitalization of electroencephalography in the neurophysiological laboratory. This change is good for hospital affairs both economically and ecologically. Board certified doctors or technologists by the Academic Society in Neurophysiology are increasing each year and are improving the clinical level in daily laboratory work. One problem is that the level of neurophysiological laboratory examinations differs among hospitals in Japan, but they are showing a gradual improvement. Future development is promising in this field. Technological progress in neurophysiological functions is remarkable, including magnetic methods. Magnetoencephalography has powerful spatiotemporal resolution and can analyze higher brain function such as language, memory, calculation and so on. Transcranial magnetic stimulation is also available for laboratory examination of the nervous system, including motor and higher brain functions. In this symposium we showed cerebellar-related motor potentials in the soleus muscle by transcranial magnetic stimulation of the posterior fossa. This report summarizes the present status and future development of the neurological field in physiological laboratory examinations.

Regulation of motor representation by phase-amplitude coupling in the sensorimotor cortex.

High-γ amplitude (80-150 Hz) represents motor information, such as movement types, on the sensorimotor cortex. In several cortical areas, high-γ amplitudes are coupled with low-frequency phases, e.g., α and θ (phase-amplitude coupling, PAC). However, such coupling has not been studied in the sensorimotor cortex; thus, its potential functional role has yet to be explored. We investigated PAC of high-γ amplitude in the sensorimotor cortex during waiting for and the execution of movements using electrocorticographic (ECoG) recordings in humans. ECoG signals were recorded from the sensorimotor cortices of 4 epilepsy patients while they performed three different hand movements. A subset of electrodes showed high-γ activity selective to movement type around the timing of motor execution, while the same electrodes showed nonselective high-γ activity during the waiting period (>2 s before execution). Cross frequency coupling analysis revealed that the high-γ amplitude during waiting was strongly coupled with the α phase (10-14 Hz) at the electrodes with movement-selective high-γ amplitudes during execution. This coupling constituted the high-γ amplitude peaking around the trough of the α oscillation, and its strength and phase were not predictive of movement type. As the coupling attenuated toward the timing of motor execution, the high-γ amplitude appeared to be released from the α phase to build a motor representation with phase-independent activity. Our results suggest that PAC modulates motor representation in the sensorimotor cortex by holding and releasing high-γ activity in movement-selective cortical regions.

A novel PET index, 18F-FDG-11C-methionine uptake decoupling score, reflects glioma cell infiltration.

UNLABELLED: The linear correlation between (11)C-methionine PET and tumor cell density is not well conserved at the tumor border in glioma. A novel imaging analysis method, voxelwise (18)F-FDG-(11)C-methionine PET decoupling analysis (decoupling score), was evaluated to determine whether it could be used to quantitatively assess glioma cell infiltration in MRI-nonenhancing T2 hyperintense lesions. METHODS: Data collection was performed in a prospective fashion. Fifty-four MRI-nonenhancing T2 hyperintense specimens were stereotactically obtained from 23 glioma patients by intraoperative navigation guidance. The decoupling score and tumor-to-normal tissue (T/N) ratio of (11)C-methionine PET were calculated at each location. Correlations between the tumor cell density at these lesions, decoupling score, and T/N ratio of (11)C-methionine PET were then evaluated. RESULTS: Both the decoupling score and the T/N ratio showed a linear correlation with tumor cell density at these specimens (R(2) = 0.52 and 0.53, respectively). Use of the decoupling score (cutoff = 3.0) allowed the detection of specimens with a tumor cell density of more than 1,000/mm(2), with a sensitivity and specificity of 93.5% and 87.5%, respectively, whereas conventional (11)C-methionine PET (cutoff = 1.2 in T/N ratio) was able to detect with a sensitivity and specificity of 87.0% and 87.5%, respectively. Reconstructed images (decoupling map) using the decoupling score enabled the visualization of glioma lesions that were difficult to visualize by (11)C-methionine PET alone. CONCLUSION: The decoupling score showed better performance in detecting glioma cell infiltration than (11)C-methionine uptake alone, thus suggesting that (18)F-FDG-(11)C-methionine uptake decoupling analysis is a powerful imaging modality for assessing glioma invasion.

[Portal hepatic lymphadenopathy involved by Rosai-Dorfman disease-like changes in a patient with hepatocellular carcinoma].

We report a case of a 68-year-old woman with chronic hepatitis C who presented with a small hepatocellular carcinoma in segment 8 (S8) of liver and a portal hepatic tumor. Transhepatic arterial infusion therapy was performed, followed by partial hepatic resection of S8 and excision of the portal hepatic tumor with lymph node metastasis. Histologically, the lymph nodes showed marked infiltration of large histiocytes with clear cytoplasm and emperipolesis in the specimen stained with hematoxylin-eosin. These findings were generally compatible with the histological features of Rosai-Dorfman disease (RDD). However, immunohistochemical analysis revealed the proliferating histiocytes were negative for CD1a, CD68 and S-100 protein, but positive for only lysozyme. Therefore, we finally diagnosed it as a disease similar to RDD. This was a difficult case diagnostically distinguish between metastasis and benign disease.

Neural decoding of unilateral upper limb movements using single trial MEG signals.

A brain machine interface (BMI) provides the possibility of controlling such external devices as prosthetic arms for patients with severe motor dysfunction using their own brain signals. However, there have been few studies investigating the decoding accuracy for multiclasses of useful unilateral upper limb movements using non-invasive measurements. We investigated the decoding accuracy for classifying three types of unilateral upper limb movements using single-trial magnetoencephalography (MEG) signals. Neuromagnetic activities were recorded in 9 healthy subjects performing 3 types of right upper limb movements: hand grasping, pinching, and elbow flexion. A support vector machine was used to classify the single-trial MEG signals. The movement types were predicted with an average accuracy of 66 ± 10% (chance level: 33.3%) using neuromagnetic activity during a 400-ms interval (-200 ms to 200 ms from movement onsets). To explore the time-dependency of the decoding accuracy, we also examined the time course of decoding accuracy in 50-ms sliding windows from -500 ms to 500 ms. Decoding accuracies significantly increased and peaked once before (50.1 ± 4.9%) and twice after (58.5 ± 7.5% and 64.4 ± 7.6%) movement onsets in all subjects. Significant variability in the decoding features in the first peak was evident in the channels over the parietal area and in the second and third peaks in the channels over the sensorimotor area. Our results indicate that the three types of unilateral upper limb movement can be inferred with high accuracy by detecting differences in movement-related brain activity in the parietal and sensorimotor areas.